SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b20a2b19d91861d991858a1085e3b0b426ef393b527c2b89a1c956f23a1afda4' 
  AND token = 'ZuD/tQwM2rtahcCWGrpSakvPPKyq4YzYHc7g6gy48NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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