SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59ff3f45463d7571104fad827c33daa5d51062209be21256892e9b18052f05d2' 
  AND token = 'sJpuWxCdHeA4GBNQNYQgjvBpJjEqGPeB6z+Ohyv8ef0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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