SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59242048c137b74b89656f2a76b54f38b1c0bcd0a037c46156eade0f5a4990b6' 
  AND token = 'IJHta/1FjshzgztbOqCYyHHZih5D8ANjyIdBzUQ9GCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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