SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ad0dd6bdfced5d30472a1956679fa7f076b8d17879936859e15612510081d28' 
  AND token = 'RGVbKGSGxuI/gSN0Dl+a1xeFxYxflZjkshl7pOWDTio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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