SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f559c2a07e17fd599ac0d2423fef06beae57e3bdf164978d185830c968e7337' 
  AND token = 'j+GOK12UGPb+wtEw12TXr0CYPPkPGVS3xXiZHu//n/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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