SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c24df98c7aa8fe7f477e4301a545e61ea2a78507556716ee9f0dacd360d5d502' 
  AND token = 'qvAYVrzBJQlqNreF9wXz967rWdxVb0Cgg/w3drQUH+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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