SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e791589fbf01f70dbcf3610a9a2c09682afadb2dbd22c200afb79576be753320' 
  AND token = 'vsmcLx/UOo9fVrU/PFiaYGRhYXhl/+gvAGic4hZiyMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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