Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6f51df545aeb23cdf350ec9717a3e7d2548560898d2d946049d6de5a4d11eb1' 
  AND token = 'lAk/0m1t+d41yfAtPpvsV0yHZKvr1fA3t8SU+HGuGWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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