SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '875e49f56b19e574e7cc20720d0100a6e9f79dd6cea5164ffbf0031bf7738152' 
  AND token = 'TXm45AzrCG8G/VxT8iEFXlPvpJdflplLEf4CXFihzL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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