SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d2d201da896a2018095aab2f168a8c6e3a3149e21cba55af811eb52177f66e6' 
  AND token = 'xz2k3IeFM6xKzwMKfA/AY0Grx5JdcqoWntdZ7+wp4eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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