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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bfa58316150000a77027f8e9ce5a65af0427b44b769eac1bb4a7b8736aec7f6e' 
  AND token = 'G5F1g5Z8npGzLpg3WQCgRE1Qb1fDB3HsDRPQyXchBtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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