SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a24ddf4ea6cd34133e15f569789df10caac82ac8e23c6cb3883b6a976bf4f60' 
  AND token = 'M+CXqgaYseY12rNFPSfWcQr9iCXmXNefQ7yfnVIsVpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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