SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0dcc0fc43b71022508945b115483b4d9480a422084098a1b04704444eb2a933' 
  AND token = 'lQyIh74npy+zgEUBJNGvoyXfm4v3hzfZsZOAPVpxLEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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