SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af42d80449023c2d03c6634b724cc6ce058622baa51bef47839584ab1951bbcc' 
  AND token = '4otl6vstbyMKeiwcLN31Cgyj0prwhnrZHezNjlwxEPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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