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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cce24007c44a0d071961485ffd1f78cf3ae5b5199f5e0b8618667f0992c42a47' 
  AND token = 'rwxX2vX4AWXuop5Kc09yBpp1AjjtNTA+ZE9bYb+Tn9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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