SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fded6e0393013ca1f5910a6c2fde4eab9d681ea6d46ebd612e301e5bf9cab3ff' 
  AND token = 'RV6iKPYnyuM+G9zGcCiM7DNkgAgnCr/NpetukClDQwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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