SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7e825126a5e5691a511d75f6e3cb8510d275b4f8b9b2c7dc5d8fcd9f7c994e3' 
  AND token = 'n3k1swiz39MFcWK+scAafI3BYP/JzGT2KW/57hABqBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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