SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b89679604cd3ff62e434e41717acc0454ec4df1672b38ea47fee58cd5107059' 
  AND token = 'RvqBVCmQNpqDhr8Xa+gcdEp/JkUlQ36BA1uugBFOmJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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