SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f76ac326257180091ae727ef3c5730a29c6d4be8c82e4302d87ff009195c6818' 
  AND token = 'BvQIWZG76qBSuYCuNog5kO4QOs7XrzHfZRams1TpWP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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