SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ee6c4471bedff8e606e41fc2f8c053b595f378cc6d51d1a67880a66ed4eea8' 
  AND token = 'qZctu5srnkDXeOH39AOFvwfAboSl/Ofn1LJL8q7KZeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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