SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecefc221c637e83aa441c1727318209698d509d0e71195625c0cd7ba6d4972c2' 
  AND token = 'L7PLVQSma0ydt5vPhq13fru7jNwOyBlz9PeOVFBLdJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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