SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e26fb2902927d2230af35db90deae0a06df242e14c02224160d3239aab123926' 
  AND token = 'BicoxjfiIDjTsNamlBs8KAAkV90EEyjB2amwmab6IAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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