SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73936664244dbf75d3fda12eed5295db1640e6b7e5dc786d08bbfbf919e9894a' 
  AND token = 'b7COqpEkGaAxNkYapO7ITNGshbvpsv2BuQwc8UaFtPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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