SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394cf2415f2690af4801794be8e16dd0cb833daf80879afc9ff762f6ec428a9c' 
  AND token = 'RIFZlD1P83KySAnmD7g1zFJWUtlQYvToFDxejsys26o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}