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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b96602cdb384ea07e3e3755af9e37ac8291bcf0447ad83f8ecc2d211540e3dad' 
  AND token = 'jFSbiFW74cS3coUraf0pvi0BDASTzX7rtHn2NGepaME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}