SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53d135f0ce2536758258ca11b0d9cf7fbeea0443c04d36a0b1e00556c44fa38d' 
  AND token = 'HZGLIFNkOmWPh0Q9AeDxjgLc/KW5wfTo1aIKl3BWXiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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