SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d1d02387ada99ac10807be799a1c3032b7c4abcbec48ccdfd5304bd4ba3783' 
  AND token = 'If4ffngaU6Nsykghp4TqC3Flh553DZ48/RGj7jhe/qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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