SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '469c68a73e9aa8078cbcb7410540863c286a1eb3d41266467e444af12ef6d751' 
  AND token = 'YDFPw+HbvblbAtKzKIOEAd+pn6xFfuKrynANEPqRFao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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