SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a64f3c503234ed518d7bc7aceb81c9e838748983a067616217e147b7cee680e' 
  AND token = 'fomNZVnoBvzGqTGrjwFXvXgLDZ/MG1Up4n63kjSkAt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}