SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '465d392f95a0598dbf40495f4cdaa360aa2d63e066fd45571c07a377b3283857' 
  AND token = 'FQYgFA40539LyEOwnbzWBzyaIqdsduBuxnwWUtYeCJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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