SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdcf3142c529860f530832c5d379702f42ea68a5ce3d793ce6591814620fc706' 
  AND token = 'EnPJ2txWTgotiP1ohSxBrohBuX0q2MLH0ONJP0HnpAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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