SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6151553b9747f6695fecaae3eecad0aa9fcada9ded97936cbd9cf5c908975c11' 
  AND token = 'B0kr6HV2Z97zZaxtInSMAcaVAOxzVMkdHiWkqrn0B1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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