SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b26f2ffc0472453092b6cc84a1ca66aac625330787107686b68584d7fcfb86b' 
  AND token = 'nXTN3RZpGRuAfHmXsNACYguoO5yCE5zFxucWkSUZC2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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