SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f91d0be09dd040619aded841d2d72f14953d6c2949abe5de590be6780768ea' 
  AND token = 'puq0yKGs6nXviI9l0tKrOogh91UJDMtrnfm+NF8ZURE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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