SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ae4bb75508c3a7c8d6ae28be1e11ae9a528829c1e7d6f4a0fcbdd258fae5295' 
  AND token = 'cn0TcJiSJrlisZ+u3SI6k2P86W1zjs3+UGAhe5d1mtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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