SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1b2d1f1b3de5a576106c3c5bd9e57a9ed7feeb443219f092fe8234cd922c94a' 
  AND token = 'joW137SH4lpsBmN0uvNvrfyDQvVFCfQDb5vRJSrL6ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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