SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25eecb82ee360afd92845352deb3009d98d813efcffe38195481c88d484adbb2' 
  AND token = 't3YPFtMRFgcDXhSnLYGCxcKhMxbSkwRbPGpfDGVYWKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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