SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaf187438be61191b8f0a04851f5da42c840079e11d90d05bf4ad80cbea89d17' 
  AND token = 'QsqDWW/TipbAjn9Olcq/7qpqm8/uA+0pbvdlgdTWir8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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