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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6676bc43b4e8bc8b5a1f32fe62d0e3f873b02977d8a9cbd73d7de84e6c8201b1' 
  AND token = 'aDCLf57gw8yqg7o/TDoYM/reMwRJxCAsVtPMvP6vh5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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