SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '195a82326585ee57f6de9a8fd3f3e4082b58568bbecc6dcab7b5161522ed966a' 
  AND token = '46oL1UCqMxB0XSajBn8fym/u2EPPutYrsGfPtplZRXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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