SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5b3e41e399331fc61dfda8b2b1135f2e4e8d9caade16018b796eb0117e3cc694' 
  AND token = 'RMJuVsJF9Jzqk9ULYNMg6Me33qpSScnX355ZFx2pKGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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