SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf19f53f1574520370a8be640ee1b1c0c7398989f4ac8bac1cf5e47dbd8c2fb' 
  AND token = 'Fvijm/QsPPxbnESQ8u7wlBaXf+LpbBwCG/Y1imGPGKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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