SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '291aa618cc2c6ead9ae14b1b67d50d20f03aa9df9ca2da68e0b86102570278d2' 
  AND token = 'P1PLqmn0yRuzN9lyNB+gWJPExOnGgTiWODh+Ueki1+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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