SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7af8a3b4355982d8a0e5b6a712ad8741311b8cba0e37ee5773815b12489c1a6' 
  AND token = 'aiXwfJbJdzaS1nByiCes4OcYgc9Tu4wVbQcJm+yeVRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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