SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d5a8207562471e2b07926f28644228d9353405861e136f529f57580e8ab94d1' 
  AND token = 'Yc5YPALG+uH01uBjZFHpoS9YxTWvajatD3J+qg4s2XQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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