SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c39d71bbb312073da598b669789619726401cf87cbd44595041dd23c530408' 
  AND token = 'gbPvocsytUrbzAEqR/Z29A25Mmf61uePxWzWsetnakI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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