SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a10cb3751e2e743976bd305b2cac7d11fbd56277eca85c4b74339f8ab062b8' 
  AND token = 'eR1sTuZsRXkF2Te13q94Qvytx5GKs+iPriktJAgy/bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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