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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5af75e94cd464ce06c9ed6915f41734fc926d1c8e468bd834df5e8fa17ccabcd' 
  AND token = 'nZ/NQj/Se84U9Jx0UJUth1OGlzIoESRapJ1SvHsEjmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}