SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e6a980640d46099d62151aea09c446c1749f7c6ca75728c9eb45761aff3244d' 
  AND token = 'JTCvIBOOCqUEonyw5WFvTflyjTxLiTxgmJZSPROI6Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}