SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdcdfe36093d71ba02e3251e85ab4842357313285574e15693007c86c9bcd25b' 
  AND token = 'aFXr79gthZpIbXxzGA2hE8rr4DfbsYqGb7f9uvgb0Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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