SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e1a1933a8d7cda5706066438ead30fd3b761f904e2a815776fb48e046bdb7e4' 
  AND token = 'uY1EE287zpO4UmjHpfCsqvrfit+L9efbvFtPjQkwbw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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