SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3983cc7b07d5b8ab6d7a832f573cc316f5b4e60bfc1867b1e35d0a680e2e0467' 
  AND token = '4+CGPM+QTq0Iw+AyF/g4OHjbHmZ1VXRGnu+pJqlvSmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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