SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac185ad37228702b2cda63c135babb2d7617ceca229637a60551a62b63958f5' 
  AND token = 'TpDXUQcPPs9v0es6+YV6kzW1KRSiJcHAZcDJUHS2KIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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