SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e618993410e283bf146eb733fc7d3cdf8bc6ae843b269dfcd13989956038208' 
  AND token = 'FZbxrr6F1SiyznsOCo/x8ej6usJDEttohMM8z7+IfFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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