SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6623e192528b83f37e9cd3b5057c6c1e115c6a563d38923a9b6ee079d0360ba' 
  AND token = 'RCwYVHoPws4Bg4EPYBMEbBmjeyupF4WaE3WgumWXmxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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