SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb448cece051d5f534c44279e99bbe4657a8a66a5e7810e4598426b48a196497' 
  AND token = 'r7g/kC9JYYTpL83a8GRvJx+UTdmcs99XjZwIN/qaKUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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