SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e3280b55e730247a70ece3939597b58efb7766c811af7a93b1b69793ba81a9' 
  AND token = 'yBx/ieTMngjjJLsA5Z+UeeNBVKYT20SAOPAHZcZdYnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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