SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab902ca4e8a86d080dfa1acd05e32ab08723748eb2c5580812caee17e3c413a' 
  AND token = 'CgwCQOe/Y+Z20aKUtQLlGCRkQ2xBCNsALoVDMEPqzLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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