SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5f1343786a14e85c9587cbe781fae8a2fce41811618cf69726405c6c43424f1' 
  AND token = 'O+udTwxFY8lZZz64W7qgKwYzZ3RaNdV51zhSqrOWsUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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